This invention relates to the problems associated with mounting an integrated circuit or transfer onto a printed circuit board in such a way as to adequately secure the integrated circuit to the board, make an adequate electrical connection to the contacts on the circuit board and make sufficient contact with a heat sink device for heat dissipation purposes.
Devices for securing similar circuitry to circuit boards are described in some of the following U.S. Patents.
In U.S. Pat. No. 4,259,685 to Romano; "Clamp for Securing an Encased Power Frame to a Heat Sink", a heat sink clamp is disclosed for maintaining an integrated circuit flat against the base to which the circuit is mounted.
In U.S. Pat. No. 4,054,901 to Edwards et al.; "Index Mounting Unitary Heat Sink Apparatus with Apertured Base", a unitary heat sink is disclosed for maintaining the integrated circuit body flat against the heat sink base.
In U.S. Pat. No. 4,288,839 to Prager et al.; "Solid State Device Mounting and Heat Dissipating Assembly", a retaining device is disclosed upon which a solid state device is positioned. Incorporated in this securing means is heat dissipating means. This is more distinctly shown in FIG. 3.
In U.S. Pat. No. 3,519,889 to Monaco; "Assembly with Transistor Heat Dissipation", a clip is disclosed to mount the transistor to a body which is composed of heat sink material.
In U.S. Pat. No. 3,548,927 to Spurling; "Heat Dissipating Retainer for Electronic Component", a resilient clip is disclosed which is designed to be attached to a heat sink member.
In U.S. Pat. No. 3,893,161 to Pesak; "Frictionally Engageable Heat Sink for Solid State Devices", a heat sink for solid state devices is disclosed to frictionally engage the solid state device.
In U.S. Pat. No. 3,641,474 to Owens; "Semiconductor Mounting Structure", a capsule is disclosed for mounting a semiconductor device in such a fashion to allow the leads of the semiconductor device to be inserted into a connector socket and the semiconductor device along with the capsule to be affixed to a heat dissipating metal plate attached to a circuit board.
In U.S. Pat. No. 3,801,874 to Stefani; "Isolation Mounting for Semiconductor Device", an isolation mounting is disclosed for semiconductor device to fasten the semiconductor against an insulator and thereafter a heat sink plate.
In U.S. Pat. No. 4,215,361 to McCarthy; "Winged Self-Fastened Heat Sinks for Semiconductor Devices", a one-piece sheet metal heat sink is disclosed with internal fingers to engage and hold the semiconductor device.
In U.S. Pat. No. 3,694,703 to Wilens et al.; "Heat Dissipator for Encased Semiconductor Device Having Heat Tab Extending Therefrom", a heat dissipator is disclosed to encase a semiconductor device, the dissipator being made of a stamped sheet metal body with a slot to engage the heat conductive tab on the semiconductor device.
In U.S. Pat. No. 3,786,317 to Thierfelder; "Microelectronic Circuit Package", a mounting mechanism to isolate the semiconductor device from applied stress is disclosed.
In U.S. Pat. No. 3,213,324 to McAdam; "Variable Cooler Unit", shows one of many available heat sinks.
In U.S. Pat. No. 4,100,566 to Okikawa; "Resin-Sealed Type Semiconductor Devices and Manufacturing Method of the Same", a resin-sealed semiconductor device is disclosed which has a heat dissipating plate mounted on a mounting plate with means to prevent occurrence of cracks in the resin portion.
In U.S. Pat. No. 4,095,253 to Yoshimura; "Single In-Line High Power ResinPackaged Semiconductor Device Having an Improved Heat Dissipator", illustrates another type of heat dissipation fin-type device.
The subject heat sink was modified to its present configuration to increase disspation of the heat generated by the semiconductor device and to ease assembly.
When semiconductor devices requiring heat sinks are assembled, labor intensive hand operations are required. In addition, since semiconductor devices requiring heat sinks obviously generate large amounts of heat, testing, in addition to the normal production operational checks, must be done to assure that the heat sinks and semiconductor devices are properly mounted onto the circuit boards. The use of extreme testing conditions requires that the heat dissipation be adequate enough not only to handle the normal running conditions of the circuit, but also to handle the greater than normal heat conditions encountered during testing. In addition, labor intensive devices not only slow down the assembly process of the entire circuit board, but increase the cost of manufacturing and increase the likelihood that the circuit board and/or semiconductor device will be mishandled or dropped, thereby weakening the connections mechanically or electrically.
Therefore, it is an object of the subject invention to provide a heat dissipation means for a circuit board mounted semiconductor device which provides adequate dissipation for heat generated by the device during circuit operating conditions and testing conditions.
It is a further object of the subject invention to provide a heat sink for a semiconductor device which will minimize manual assembly onto the circuit board during the manufacturing process.
It is still a further object of the present invention to provide a heat sink for a semiconductor device with an efficient heat transfer between the semiconductor device and the surfaces of the heat sink and the circuit board.
It is still a further object of the present invention to provide a heat sink which will allow for the firm affixation of the semiconductor device and the heat sink to the circuit board without disturbing the die bond of the semiconductor device.